I'm sayin me and you are both in the same spot as far as what we can/cant do or say, we don't dictate laws.
As for the straps, If they was legit they wouldn't be gettin popped for it.
Girls gone wild is technically, yes, illegal, and constitutes public nudity. But there are some things police don't roll as hard on. Large parties, etc. Just like on New Years you know it's illegal to drink in public, but mothafuckas be still swiggin that shit on the streets.
As for Mardi Gras, the New Orleans city council wanted to ban it, saying it was rude, broke the law, etc., but too many people came out against it.
Live concert acts are attended by police, thus illegal activity there is usually swooped on the second it happens. Guns N Roses, Madonna, Prince, 2 Live Crew, all have been charged with violations that occured on stage during a concert.
A Non-rap example would be when Lynn Strait(RIP) from Snot came out on stage with some girl suckin his dick. He got rolled by the local whoever PD and charged with lewd conduct which I believe is a misdemeanor.
Do misdemeanors or small violations happen in large numbers AKA Girls Gone Wild and Mardi Gras? Yes, but for the most part, when police watch over large gatherings, they tend not to arrest for petty shit to keep the crowd down.
That's how most celebs get busted for prostitution. Two people ass naked fuckin in a car is illegal and constitutes public nudity and lewd conduct. WHen they get rolled up on, surprise, there's also a known prostitute in the car, which is how the recent Hugh Grant thing happened.
Edit: Stripping takes place inside a non-public building. And most Wet T shirt contests, Girls Gone Wild parties, etc., usually take place on private beaches, or in warehouses, etc. Also you gotta figure will the Police roll up on a huge ass party during spring break and prosecute? Nah, they got better shit to do. Will a cop watching a concert make arrests and prosecute? Why not, they ain't got shit better to do.
Also you know girls be showin titty at concerts and nobody rolls on them.